Appendix G overview

As part of a trial change to the SoW process, National Grid Electricity Distribution (NGED) provides NGESO a list of relevant embedded generation connected beneath each Grid Supply Point (GSP). 

This contains the list of connected generation sites and those committed to connect, including size and technology. This list is the ‘Appendix G’ and is attached to our formal agreement with NGESO at each GSP and can be viewed in summary on our website.

Part 1 - Contains previously connected sites where general Site Specific requirements do not apply.

Part 2 - Contains Connections where Site Specific requirements apply.

Part 3 - Contains Connections that are subject to interim restrictions and Site Specific requirements also apply.

Part 4 - Contains Committed Connections that will not be able to connect until works on NETS are complete.

Part 5 - Provides aggregated capacity of Sites in Part 1 to 4. It also provides an indication of any additional capacity that may be available on NETS. The available capacity is described by two terms, Materiality Headroom and Fault Level Headroom. Allocation of such capacity is dependant on a monthly submission and approval process under this trial.

If there is sufficient Materiality Headroom and Fault Level Headroom NGED will submit your scheme to NGESO via a monthly Appendix G update. When the Appendix G is approved by NGESO we will inform you of the outcome and advise if any modification to your connection offer is required. Please see SOW process flow diagram for typical timescales.

When the volume of accepted generation connections exceeds the Materiality Headroom or Fault Level Headroom at a GSP, NGED will need to make an application to NGESO to identify if any works are required on the NETS. Depending on the complexity of the studies this will prompt either a Project Progression or Modification Application. Customers who trigger this process will be required to fund the fee applied by NGESO for the application and will need to wait for the outcome of NGESO's assessment. The Project Progression / Modification Application fee will range from £18,750 to £40,600. 

NGESO will provide a response within three months of receiving an application from NGED. When NGED receives the outcome of the application, we will write to you to inform you about any potential implications, fees and amendments to your connection offer. All GSP’s currently going through a Project Progression will be listed on our web site along with anticipated dates of when we will know the outcome.

Materiality Headroom is that additional MW capacity that might be available for further generation connections to the GSP.

Fault Level Headroom is that amount of additional fault level that might be available for further generation connections to contribute to the GSP.

For further help please contact nged.sow@nationalgrid.co.uk

(Emails will be answered between 8am-5pm, Monday - Friday)